view article
Figure 5
Representative raw resonant X-ray magnetic scattering results on Cd2Os2O7 at ten different pressures, out of 30 total measured pressure points at T = 4 K in the work by Wang et al. (2018BB61). The displayed raw data cover six out of the ten highest pressure points explored above 25 GPa, spanning the magnetic quantum phase transition at Pc = 35.8 GPa. The panels demonstrate in parallel both the sample-mosaic profiles (at E = 12.387 keV) and the energy scans at different azimuthal angle φ around 45° relative to the (0, 0, 1) azimuthal vector. At each pressure, we typically study 5 to 12 different azimuthal angle positions, depending on the level of multiple scattering and the convergence of all resonant spectra. The presentation here is limited to three to five sets of azimuthal positions for the sake of clarity, leaving out scans at azimuthal positions which show significant multiple-scattering contamination. The collective set of energy scans is used to determine both the presence and true intensity of the magnetic diffraction, using the lowest common spectral weight designated by red points of either one spectrum or a combination of several spectra. The magnetic diffraction intensity was integrated from sample-mosaic rocking curve(s) of the cleanest energy-scan curve(s) at the resonance energy E = 12.387 keV. This allows one to both remove a θ-independent sample fluorescence and minimize the multiple-scattering contamination. At 36.7 GPa, above Pc = 35.8 GPa, the minimal spectrum of the energy scan differs in shape from a resonance profile. Instead it is similar to the shape of the L2 absorption edge, indicating that the rounded shape of the energy scan at 36.7 GPa is caused by Os fluorescence. Although all magnetic diffraction intensities at the (6, 0, 0) order are eventually normalized by the (4, 0, 0) lattice diffraction intensity in the π–π′ channel, in order to correct for both the sample size and mosaic difference, our sample mosaic is kept at or below 0.5° FWHM to efficiently match with the polarization analyzer's mosaic width. For clarity, only the results of the π–σ polarization switching channel are shown here; diffraction results from the π–π′ channel can be found in the work by Wang et al. (2018BB61).

IUCrJ
Volume 6| Part 4| July 2019| Pages 507-520
ISSN: 2052-2525
https://doi.org/10.1107/S2052252519007061